Section 1

Introduction

This document describes the history and various processes involved in
the planning and conduct of the 1986 Census of Population and Housing,
and the types of output available. Detailed information on specific outputs is
contained in Census 86 -Data Release Plans (2173.0).

Since 1961, the Census of Population and Housing has been
conducted every five years. It is the largest statistical collection undertaken
by the Australian Bureau of Statistics (ABS). All persons in Australia are
enumerated at the dwelling in which they stayed on census night.

The census is one of the most important sources of statistical information in
Australia. It provides a unique source of demographic and social information
for a variety of geographic areas. Statistical outputs from sample surveys are
generally limited to estimates of large geographic aggregates because of the
high level of sampling error associated with smaller figures. Censuses are not
affected by errors of this kind (although reporting and other errors remain).

Census statistics provide an essential basis for the preparation of population
estimates at the national, State and local government levels as well as a
benchmark for numerous surveys conducted by other bodies in the public and
private sector.

They are also used:

for decision-making activities that affect the lives and welfare of all
Australians,

in researching social issues; and

as a basis for planning by governments, other institutions and the
general public.

On 30 June 1986 the ABS also conducted a census of the population of two
of the Australian external Territories, Cocos (Keeling) Islands and Christmas
Island. This is the first census in which the ABS has completely undertaken all
census operations in these Territories, including dissemination of census
data.

The population of these external Territories is not included in the total
Australia population.

The history of census taking in Australia

The first population counts of Australia were known as musters and were
made as early as 1788. The first census in Australia was that of New South
Wales, held in November 1828.

Censuses conducted by each colony continued until 1886. On 3 April 1881, the
first simultaneous census of the British Empire covering the United Kingdom,
India, and the Crown Settlements (including Australia) was taken. This census
produced the first set of colony population figures enumerated on the same
day.

A Census Conference held in Sydney on 26 February 1900 arranged for the
collection and compilation of an Australian census on a uniform basis to be
taken on 31 March 1901. Minor differences in the interpretation of definitions
arose between the States, and the method of presentation of the results
differed considerably. The responses to the census questions were not tabulated
in all cases and there was no coordinating authority to bring the results
together to form a total for Australia.

To provide greater coordination, the Census and Statistics Act 1905 was passed
on 8 December 1905. This Act provided:

(a) `that the census shall be taken in the year 1911, and in every tenth year
thereafter'; and
(b) 'the census day shall be a day appointed for that purpose by
proclamation'.

On 18 June 1906, the first Statistician of the Commonwealth of Australia was
appointed, and it was the duty of that officer to carry out the provisions of
the Act. Later in the same year the Commonwealth Bureau of Census and
Statistics was formed (re-named Australian Bureau of Statistics in 1975).

Since 1911, therefore, the census has been a centralised activity conducted and
controlled by the Australian Statistician under the authority of an Act of
Parliament to ensure uniformity in the census methods and data collected from
each State, and to protect the confidentiality of information gathered.

Because of the economic depression it was considered ill-advised to conduct the
scheduled Census of 1931, and the Census and Statistics Act was amended so that
the census could be held at any such time as prescribed. Under the amended Act
the next census was held in 1933. No census was held during the period of World
War 11 and the first post-war census was taken in 1947 after an interval of 14
years. The year 1954 was chosen for the next census, it being a seven-year
interval and equidistant between the 1947 Census and the then proposed 1961
Census. The practice of conducting a census in at least the first year of each
decade was thus resumed from 1961 onwards.

In the selection of census day, every endeavour is made to choose a date when
there is a minimum displacement of population. In 1911 and 1921, census day was
near the beginning of April, but in 1933 and subsequently, census day has been
at or near the end of June, because this time has better fulfilled the
condition mentioned and is otherwise suitable, being the end of the fiscal
year, and of a quarterly period used extensively for statistical purposes.

Following the 1961 Census, Australia has had a census taken every five years, a
practice which has now become mandatory with the amendment to the Census and
Statistics Act in 1977 requiring that 'The Census shall be taken in the year
1981 and in every fifth year thereafter, and at such other times as
prescribed'.

Selection of census topics and question design

Planning for the 1986 Census of Population and Housing commenced in
November 1982 after Government approval was received to proceed with the
development of the census on the understanding that the content of the census
household form be no greater than that of the 1981 Census. Once this
approval was obtained, all known 1986 Census. Newspaper advertisements
also invited public submissions.

An open assessment users of census data were invited to make submissions on
topics to be included in, or excluded from, the of topics submitted by users
and the public, supported by objective field tests of topics (in particular for
topics likely to be difficult or sensitive), is regarded as the best method of
developing a census form most acceptable to the public, and for optimising the
value of the statistics produced. Previous experience in Australia and overseas
has shown the critical importance of public cooperation.

The Census and Statistics Amendment Act (No 2) 1981, proclaimed on 1
March 1983, removed the requirement of the Census and
Statistics Act 1905 that certain topics be included in the census and others be
prescribed by regulation. All future census topics were to be prescribed by
regulation.

The 1986 Population Census Ethnicity Committee

During the development of the 1981 Census household form, difficulties
were encountered in developing a census question on ethnic origin to meet a
strong user demand for data on this topic. Consequently, a small committee of
persons with special interest or expertise in the matter was established in
December 1982 to advise the Australian Statistician on questions
relating to ethnicity.

All topic submissions relating to ethnicity were made available to the
committee. The committee issued a press release inviting further submissions
from interested persons and organisations. A report from the committee to the
Australian Statistician was released by the ABS as an information paper The
Measurement of Ethnicity in the Australian Census of Population and Housing(2172.0). The report recommended that a question on ancestry be asked in
the 1986 Census and a question was included along lines suggested by the
committee.

Evaluation of topics

It is essential that census topics be well justified, due to the high cost of
collecting information in a census, and the burden placed on the public who are
required to provide the information. For many topics, sample surveys are a more
appropriate means of collecting information required by users, as they are less
expensive and impose less of a burden on the public. There are, moreover,
topics for which information cannot be gathered satisfactorily by the census
self-enumeration methodology.

For the 1986 Census, each topic submission was carefully examined to
assess the importance of the topic, possible alternative data sources, the uses
to be made of the data, and whether the justifications for the topic were
adequate. Other factors taken into consideration included: whether the topic
was asked in previous censuses; whether data were considered to be required
every five years; results of previous tests of the topic; overseas experience
(mainly the United Kingdom, Canada, New Zealand and the United States of
America); whether the topic was suitable for inclusion of the census; and
whether the census was an appropriate method of collecting the data. A number
of topics required field testing in order to evaluate their suitability for
inclusion in the census form.

Associated with the task of topic selection is the design of questions for the
census form. Field testing is an essential aspect of question design. For the
1986 Census, a program of field tests was carried out in 1983 and 1984 to
evaluate new topics (including ethnicity) and to improve questions on regular
census topics. For each test, an appropriate sample of dwellings was selected
with samples varying in size from 250 dwellings to 5,000 dwellings. Census test
forms were delivered to households, completed by household members and
collected after the reference date. Household members were asked to give
information in respect of all persons present in the household on the specified
date.

After collection of the completed forms, interviews were held with a sample of
respondents. in most cases, dwellings were selected for follow-up interview
where responses were of particular value for question re-design. However, where
the pilot test was small (up to about 500 dwellings), all respondents were
interviewed. The main purpose of these interviews was to examine respondents'
understanding of the census questions and, where possible, to determine the
accuracy and completeness of responses. Pilot testing also examines other
issues including reasons for people not being enumerated, sensitivity to
particular topics, form layout, and question wording.

Topic evaluation concluded in late 1984 with the publication of the information
paper Preliminary ABS Views on the Content of the 1986 Census (2171.0).
These views were first discussed with the Australian Statistics Advisory
Council (ASAC) and then released for public comment. After assessing comments
from the public and ASAC, the Australian Statistician made recommendations to
the Government in September 1984 on the content and estimated costs of the 1986
Census. This submission incorporated the recommendations of the Population
Census Ethnicity Committee.

Government approval of topics for the 1986 Census was obtained in February
1985. The household form was finalised in March 1985 and the eight million
household forms and supporting documents were then printed.

A dress rehearsal based on 24,000 dwellings was held in July 1985 to test field
and processing procedures. As well as providing valuable information on
operational problems, the dress rehearsal was essential for providing estimates
of coding and processing rates for finalising the budget of the Data
Transcription Centre.

Final content

The content of the final 1986 Census household form differed from the 1981
Census form in the following significant ways:

(a) The concepts of household and family heads are no longer recognised by the
census. Householders were instructed to complete the household form with the
householder or any adult household member as 'Person 1' and the spouse/partner
as 'Person 2'. Family structures were created with reference to Persons 1 and 2
and outputs will no longer contain tables with the variables 'household head'
and 'family head'.
(b) A change in question 4 on relationships within a household made it possible
to produce statistics on de facto living arrangements and children in blended
families. For the purpose of identifying families for coding in the 1986
Census, de facto relationships were treated in exactly the same manner as
married relationships, although couples were coded as married or de facto.
(c)A question seeking details of usual residents temporarily absent was
included for the first time in an Australian Census to allow family members
temporarily absent on census night to be included in the coding of family
structures. This overcomes the problem created by absent spouses in previous
censuses, leading to overstatement of the number of lone parent families and
understatement of the numbers of families with both parents normally resident
in a household.
(d)The 1981 Census question on attendance at an educational institution was
expanded by asking persons attending an institution to indicate from a
self-coded list the type of institution being attended.
(e) Question 15, on ancestry, asked for the first time in an Australian
Census, and Question 17, on language other than English spoken at home, were
included as recommended by the Population Census Ethnicity Committee. The 1981
Census did not seek languages other than English spoken at home.
(f) The question on the material of outer walls of the dwelling asked in
previous censuses was removed.
(g) An additional question on a person's occupation seeking information on
tasks or duties performed was asked to allow occupations to be coded to the
Australian Standard Classification of Occupations. This classification has
replaced the Classification and Classified List of Occupations used at the 1981
and earlier censuses.
(h) To provide a better basis for fertility analysis, the 1986 Census asked
persons in what year they were first married. In 1981, married persons were
asked the duration of their current marriage.
(i) Question 14 asked whether each person was an Australian citizen. Only two
responses were possible - yes or no. In the 1981 Census, each person was asked
to state their country of citizenship and the responses were coded to 21
citizenship categories.

A number of minor changes were also made to some of the questions, which could
have some effect on comparability of data between censuses. Users of the data
should check the wording of questions carefully when analysing data from the
census.

The census field operation

Preparing for the census

The production of accurate maps for use by census collectors is important to
the conduct of the census.

The basic unit of collection for the Australian Census is a Collection District
(CD). A CD is generally a census workload area that one collector can cover
delivering and collecting census forms in a specified period (seven days before
and 12 days after census night). A typical urban CD contains between 200 and
300 dwellings, while in rural areas a CD may contain very few dwellings yet
cover an extensive area. In output of census data, CDs may be aggregated to
form larger geographic areas (for example, statistical local areas (SLAs),
legal local government areas (LGAs), Commonwealth electoral divisions).

States are divided into census divisions, whose boundaries generally coincide
with Commonwealth electoral division boundaries, and have, on average, a
population of about 100,000 persons. Census divisions are divided further into
census subdivisions, which contain approximately 10 CDs.

As far as possible, comparability of CD boundaries is maintained between
censuses. Where a CD has grown too large to be handled by one census collector
it is split into two or more CDs, so that when aggregated they are still
comparable with the previous census area. CD boundaries are aligned with LGA
and other statistical boundaries and, therefore, vary slightly from previous
census CDs where boundary changes to the larger spatial units occur in the
intercensal period. In the case of population decline in a CD, the original CD
boundary is maintained for comparability.

The production of census collectors' maps was undertaken jointly by the ABS and
the Division of National Mapping (Department of Resources and Energy). Each
census collector received a detailed map of his/her CD.

Public awareness campaign

An extensive public awareness campaign was conducted prior to and during the
collection phase of the 1986 Census. Its aims were:

(a) to promote public awareness of the census, and the reasons for conducting
it;
(b) to explain the nature and content of the census; and
(c) to advertise how assistance could be obtained by respondents in completing
the census form (eg. telephone inquiry service and telephone interpreter
service).

The campaign is an important factor in obtaining cooperation from the public so
that high quality data are obtained.

The collection

An efficient field operation is essential to the success of the census. As in
previous censuses, the 1986 Census was self-enumerated. Each household was
asked to fill in the details required on the census form. Assistance from the
collector or the telephone inquiry service / telephone interpreter service
could be obtained if necessary. Forms were delivered to each household in the
week preceding census day, and collected by the same collectors within 12 days
after census night.

A hierarchical structure of field staff was used for the delivery and
collection of census forms. Since the 1921 Census, the Australian Electoral
Commission has made available its network of regional offices and personnel to
help supervise the collection system.

In some States extra supervisory staff were recruited from the general public,
along with group leaders (generally controlling about 10 census collectors),
and the census collectors themselves.

All field staff were appointed under the Census and Statistics Act 1905and were subject to the strict confidentiality provisions of that Act.

The group leaders were responsible for training and supervising the work of
approximately 10 census collectors to ensure accuracy and completeness of
coverage within their areas. Where households had refused to complete a census
form, the group leader was required to return to these households and attempt
to obtain the required information.

The census collectors were required to deliver forms to every household in
their CD in the week prior to census day. If a contact was made on delivery,
the collector arranged a time with the householder to collect the form after
census night. Collectors were then required to return to each household and
collect the completed forms in the 12-day period following census night,
checking each form to ensure that it had been adequately completed.

There were 29,632 CDs in Australia for the 1986 Census, and almost as many
census collectors.

Special enumeration procedures

Special envelopes were provided on collection for persons who did not wish to
have their completed form seen by the census collector. Envelopes were also
provided to persons in private dwellings who did not want their responses to be
seen by other members of the household, and for persons enumerated in
non-private dwellings. Members of the public were informed of the availability
of the special envelopes through the public awareness campaign, census
brochures and the census form.

For the enumeration of non-private dwellings (such as hotels and hospitals),
special collectors were used to distribute census personal forms (as opposed to
household forms) and privacy envelopes to each person spending census night in
that dwelling, and to collect the completed forms as soon as possible after
census night. In most cases, these special collectors were nominated by the
owner/manager of the non-private dwelling.

Similar procedures were adopted for persons in transit on census night. Persons
on board ships in or between Australian ports, or on long distance trains or
buses were required to complete personal forms. They were then allocated to a
special CD designated 'migratory' within the respective State of destination.

Separate collection procedures were also developed for Aboriginals. Special
Census Field Officers were appointed to inform Aboriginal communities and
organisations about the census and to elicit their support. Where necessary,
special enumeration arrangements, involving the employment of approximately
500 Aboriginal census collectors, were established by the Census Field
Officers. A special census form to be completed by interviewers was developed
for use with the Aboriginal population in remote areas. Support was received
from government departments and other organisations, concerned with Aboriginal
services.

For the 1986 Census, households in caravans etc. in caravan parks were provided
with household forms to enable statistics to be produced on the families living
in caravan parks. In previous censuses, each caravan park was enumerated as a
non-private dwelling, with each occupant completing a personal form rather than
separate households completing a household form.

To ensure that public inquiries concerning the 1986 Census were dealt with
speedily, the ABS established a Telephone Inquiry Service Centre in each State
and Territory.

As well as providing a mechanism for answering public inquiries concerning
census procedures and the completion of the census form, the Telephone Inquiry
Service provided feedback to census field staff where further action in the
field was required.

The service operated from 23 June 1986 through to Friday 18 July 1986, thus
covering the entire delivery and collection phases of the field operation.
Evening services were also provided during the week prior to census night, and
were extended according to local demand.

A special feature of the Telephone Inquiry Service was the provision of the
Census Interpreter Service. This service was established to handle any queries
which could not be readily answered in the English language. Where Census
Interpreter Services operators could not answer in a particular language,
'on-call' interpreters, operating from their own homes, were contacted.

Input processing

The Data Transcription Centre (DTC)

When all the forms had been collected in the field, they were sent to the
census DTC, where the number of persons and dwellings in each CD on the census
forms was reconciled with the collector's record book, responses coded, and the
coded information transferred onto computer files. No names and addresses were
recorded. For the 1986Census this involved the following steps:

(a) Preliminary check
This process included

a preliminary check, which was designed to ensure that the number of
persons recorded on the forms for each CD was consistent with the number of
persons recorded in the collectors' record books for each CD; and

coding of non-private dwelling type.

(b) Family, internal migration and qualifications coding
This process included coding of family, usual residence (to
State/Territory and statistical local area level) on census night, one year
earlier and five years earlier; and educational qualifications.

(c) Origins and language coding
This consisted of coding of birthplace of the individual, birthplaces of
mother and father, ancestry, religion, and language (other than English) spoken
at home.

(d) Occupation coding
This process involved the coding of occupation using the Australian
Standard Classification of Occupations ASCO). An extra question on the main
tasks or duties that a person usually performs in his or her job was included
to assist in the coding of occupations at the unit group level.

(e) ASCO/CCLO link
Previous censuses have coded responses to the occupation question using
the Classification and Classified list of Occupations (CCLO), but in 1986
occupations were coded to a new classification, the ASCO. To aid comparison
between the 1986Census results and those of the 1981Census, a
link between ASCO and CCLO has been produced. This link was derived by coding a
five per cent sample of census occupation responses in accordance with both
occupation classifications. This link allows users to continue with research
and time series analysis even though the classifications have changed. ASCO
will be the basis for occupation coding for future censuses.

(f) Industry and place of work coding
This process involved the allocation of codes for the industries in
which employed persons work (using the Australian Standard Industrial
Classification (ASIC)), for work location of persons in CDs in selected areas
(for journey to work studies), and for industry sector of employment
(Australian government, State government, local government and private
sector).

Industry, industry sector and place of work codes were determined, where
possible, by reference to the Industry and Destination Zone index. This index
is a pre-determined listing of all establishments in Australia known to the ABS
which are involved in various economic activities carried out by companies,
partnerships, government departments, etc. It contains, for each establishment,
the relevant ASIC code, industry sector code and destination zone code. The
index was obtained from an ABS register which was compiled and updated from ABS
statistical collections, and other sources.

(g) Data entry
This process involved the direct key entry of all codes from the census form
into computer files. Names and addresses were not recorded and were lost when
the census forms were destroyed after processing.

(h) Editing and balancing
Editing and balancing comprised computer checking of the coded data and
of CD totals to ensure that:

apparently conflicting data combinations were investigated (eg. a
10-year-old married person); and

person and dwelling totals for each CD were reconciled with CD totals in
collectors' record books.

(i) Creation of the Final Unit Record File (FURF)
The FURF is the final product from census processing. The FURF, which is
held in the computer, is a complete sequence of validated records of
statistical codes for each person, family and dwelling enumerated in the
census.

(j) Destruction of census forms
Once input processing was completed, all census forms were destroyed.
The collectors' record books used in the census field operation were also
destroyed.

(k) Quality control
For all the DTC processes, quality control functions provided information on
data throughput, processing rates, coding/keying error rates and coding/keying
error analysis. This information was used to monitor progress and to identify
problem areas in coding and data entry.

(l) Post Enumeration Survey
This process matched the responses for the name, age, sex, marital
status and birthplace of each person enumerated in the Post Enumeration Survey
to the census form on which the person was enumerated at the census. This was
done to establish whether the person was counted once, more than once, or not
counted at all; and to measure the accuracy of response to the abovementioned
questions.

Output processing

Requirements for census data are diverse, ranging from basic Australia-wide
counts of persons to detailed cross-classified information on persons,
families, households, and dwellings. Since census taking involves no sampling
error, data can be provided at many levels of detail and geographic areas.
However, there are a number of factors which limit census output. The main
limiting factors are cost, confidentiality, and the nature of requests for
output.

As each of the State and Territory Final Unit Record Files is completed and
validated, output processing commences. Output processing consists of sorting,
summing, averaging and cross-tabulating data items from the unit record file to
produce the statistics for the many uses to which census data are put. During
these processes some new variables are constructed (eg. the derivation of
household income by aggregating income ranges reported by individuals).

The ABS's large centralised computer installation, situated in Canberra,
enables the census unit record files to be stored in a way which allows direct
access by all offices of the ABS.

Confidentiality

The ABS has a long and continuing history of protecting the confidentiality of
information collected.

On the 1986 Census household form, respondents were assured that 'it would be
an offence for any information relating to an identifiable person or household
to be released'. This assurance is embodied in the Census and Statistics Act
1905. Widespread use of computers for processing and storing data and producing
statistics has increased the need for measures to avoid the inadvertent release
of identifiable information.

At the same time, the number of census characteristics tabulated, and the
meeting of requests for greater detail in census releases, inevitably produce
tables that contain very small counts. Release of these small counts might
allow the identification of persons or organisations, even though information
such as names and addresses cannot be retrieved.

Introduced Random Error

It has been necessary for the ABS to randomly adjust small non-zero cells in
the tabulations to be released in statistical publications, microfiche and
magnetic tape. These adjustments allow the maximum amount of detailed census
data to be published, while avoiding the risk of inadvertently releasing
information which could identify a particular person, household or
organisation. The adjustments also allow for a greater output of detailed data
than would be possible if other methods for protecting the confidentiality of
census data were used.

The random adjustments slightly change some of the data in a tabulation in an
unbiased manner. With very small cells, the data will be insufficiently exact
for information relating to an identifiable person, household or organisation
to be released, but the value of the tables will not be impaired. In any case,
small numbers in the original data maybe significantly affected by such things
as respondents omitting to answer particular questions or giving incorrect
answers, or by errors in coding or transcribing data in the course of census
processing.

Census counts and population estimates

The ABS releases census counts on two different bases: the census count at
place of enumeration; and the census count at place of usual residence. It also
compiles and publishes estimates of Australia's resident population.

The census count at place of enumeration is based on enumeration of
persons at their actual location on census night, and includes persons
enumerated at their usual place of residence, persons enumerated in an area but
usually resident elsewhere in Australia, and overseas visitors temporarily in
Australia. This count produces a snapshot or typical situation in any given
area on census night. The majority of census output is available on this basis
and can be provided for individual CDs, or any geographic area which can be
formed by aggregating CDs.

The census count at place of usual residence is based on the reported
usual residence of all persons enumerated on census night; usual residence
addresses are coded to statistical local area (SLA). For this reason census
output on this basis is not available for CDs or other areas not able to be
defined by SLAs.

To produce census figures for each State/Territory or SLA on a usual residence
basis it is necessary to alter the census count by:

removing persons usually resident in other States/Territories or SLAs;

removing persons usually resident overseas; and

adding persons usually resident in the State/Territory or SLA who were
enumerated elsewhere in Australia.

These counts give a better picture of the usual geographic distribution of the
population and the composition of the usual resident population by removing the
temporary effects of such factors as school holidays or seasonal employment.

The estimated resident population is the official ABS population
estimate which is derived by making two further adjustments to the census count
at place of usual residence. The first is an adjustment for census
underenumeration as measured by the Post Enumeration Survey. This adjustment is
made to counts of males and females, by age, at Australia and State/Territory
levels, and to total counts of persons at the SLA level. The second
adjustment is the addition of Australian residents temporarily overseas at
census date. This second adjustment is made down to SLA level, and is obtained
by analysis of the passenger cards which all persons arriving in, or departing
from, Australia must complete. This produces an accurate estimate of the usual
resident population of Australia.

The following diagram indicates the differences between the two different
census counts (place of enumeration/place of usual residence) and the estimated
resident population for an SLA

Sources of error in the census

In an operation of the type and size of the census there are many possible
sources of error. As in other areas of statistics, considerable effort is
directed to devising procedures to ensure the highest possible level of
accuracy is attained. While it is clearly not possible to eliminate all
inaccuracies, and some errors will survive in the final results, it is unlikely
that remaining errors will be of any significance in aggregated census data. A
series of publications containing further information on data quality will be
released from late 1987.

Major sources of error in the census

(a) Underenumeration
It is widely recognised that although the census makes every effort to
enumerate every person and dwelling (excluding overseas diplomatic personnel)
in Australia and the prescribed external Territories on census night, it is
inevitable that some will be missed. This can happen for a number of reasons.
In some instances where dwellings are difficult to define, a complete dwelling
and all its occupants can be missed. A collector may not be able to make
contact with the residents of particular dwellings for various reasons, and the
dwelling may therefore be misclassified as unoccupied and its residents remain
uncontacted. Refusal by householders to complete the census form is not a
significant cause of underenumeration and accounts for less than 0.012 per cent
of households. in about 70 per cent of these cases the number of occupants was
able to be estimated by the collector from information obtained orally from a
member of the household or other persons, and this estimate was included in the
census count.

The census collection has, since the 1966 Census, been followed by a
post-enumeration survey PES) which attempts to provide a measure of the extent
of underenumeration. The 1986 PES consisted of two parts: a dwelling coverage
check (an approximately 0.67 per cent sample of private dwellings); and a
persons coverage check (of all persons in these private dwellings).

(b) Respondent error
The editing described below cannot detect all errors made by individuals
in completing the census form, therefore, some reporting errors survive in
final output. if, for example, a respondent states his occupation as a doctor
and he is really a clerk, the census coders give the occupation code for
doctor. However, if his occupation is stated as a doctor but his age is
recorded as four years, this combination is defined by census processing rules
as unacceptable and will fail a consistency edit. In this case one or both
codes will be amended after checking with the census form to enable a valid
response to be coded.

(c) Processing error
Errors created by clerks during the processing of the census are kept
below a predetermined acceptable level by means of a quality control system. By
sample checking at different stages of the coding and keying operations, and
taking corrective action where necessary, quality control ensures that the
amount of introduced error is kept to a minimum.

Editing and associated procedures

The aim of editing during census processing is to reduce the number of errors
in the data. The kind of errors that editing procedures can detect are limited
to responses and/or codes which are inconsistent or invalid. No correction is
possible for errors which do not show up in this way. Care is taken, however,
to ensure the combinations of data which are merely unlikely, but nevertheless
not impossible, are not changed during the edit process.

In the processing of the 1986 Census no corrections were made without reference
to the census forms for responses which failed edits.

Two types of edits were applied to census processing:

(a) balancing edits were employed to ensure that all census forms in each CD
were accounted for, and
(b) consistency edits were designed to detect responses and/or codes which
appeared to be inconsistent with other responses on the same form, or in
conflict with census definitions, or processing rules.

Apparent inconsistencies in the transcribed coded census form records could
result from errors by the respondent in completing the form, or from errors in
coding or transcribing the information into the computer. Edits were applied to
detect such cases, for example, where a person was shown as aged five years and
was also shown as having a marital status other than never married. Although
the number of edit failures due to respondent error was small, there were cases
when, because of the absence of conclusive information, subsequent adjustment
of records was necessarily somewhat arbitrary.

In addition, edits are applied to ensure that codes fall into the permitted
ranges. For example, the broken sequence of numbers allocated for occupation
codes does not include numbers in the range 1320-1398; any occupation coding in
this range would fail the edit and re-coding would be necessary.

Publications

The following information papers have been or are to be released from the
1986 Census.